Whatever happened to the Secondary Selection?

For over 20 years, I have been using the secondary-selection (a standard
feature of the X-Windows system) when editing texts, using the Solaris
operating system on Sun Hardware. Recently, I have switched to Linux on
i86 hardware, and have been horrified to find that this valuable feature
is not supported by modern toolkits and editors. The world seems to have
forgotten what it was meant for, and yet I believe it is the best thing
since sliced bread.

This is not the place to explain what the secondary-selection does, and
why it should be used more widely. To see that, I invite you to visit my
website at

Furthermore, to illustrate how it is used, I have implemented an
Experimental Extension to GTK-3 so that people can try it out for
themselves and to see how useful it can be for constructing texts (and
particularly program texts, where there is a common requirement to grab
existing bits of code - perhaps even just identifiers - from other places,
whether in the same document or from outside).

My implementation is based on gtk+-3.10.8, because I am using Ubuntu
14.04LTS "Trusty Tahr", though it may well work on other Linux versions.
Yes I know 3.10.8 is ancient, but I don't expect my code, which is pretty
hairy, to be fit for immediate incorporation in current versions of gtk.
But it now works well enough for it to be tested more widely, and if
people like it, then I would be happy to join the Developer Team and to do
the job properly.

So I invite you guys to look at my website, download my code and give it a
try. I am also making this known on various other lists, because unless
people try it out (and hopefully like it), there can be no pressure to
take it further.